Will
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Post by Will on Jan 7, 2010 20:49:43 GMT
Hi Guy's.... First off I'm a noob.. so I'm going to ask some stupid questions... I've built a few projects in the past (including a full CNC controller) but have never ventured into the world of Audio /HI Fi. I bumped into this kit while looking for a logic probe kit on the Jaycar site (please no laughs) and really fancied having a go, so it's on order!!! My plan is to use this DAC, driven by a Squeezebox 3 (classic!) then out into a Krell pre/ power amp and B&W Nautilus speakers. I'd love to get the best from the kit from the start so... After reading this thread and a similar thread on DIY Audio I have a few questions which must be only to obvious to everyone else. I'll ask them and if anyone can put me on the path I'd be grateful. On DIY Audio, alfredrofe suggested these parts as upgrades. Parts used
Op Amp LM 49710
4.7 nf Polypropylene Capacitor RS 401-4766
68 nf Polypropylene Capacitor RS 401-4918
2.7nf Polypropylene Capacitor RS 401-4867
8.2nf Polypropylene Capacitor RS 401-4794
2.7nf Polypropylene Capacitor RS 401-4722
2.2nf Polypropylene Capacitor RS 401-4716 - later removed
100uf Oscon Farnell 121-7611
47uf Lo ESR Jaycar RE6332
Bead Ferrite WES FB12
Oscillator HyQ QXO8CBA 24m576
“Flea” Pink Fish Media
“Ripple Eater” Rock Grotto ForumQuestion 1 - Where do I get the PCB for the "Ripple Eater" and is this the same as the JLH that Alex mentions in every post ( jokio). Everyone on the DIY forums seems to have them falling out of their pockets but after 4 hrs of searching I still don't know where to get a kit / pcb/schematics Question 2 - It was great to get the RS item numbers however these are not available in the UK (they are AUS RS codes!). Can someone suggest alternatives which I can buy in the UK. (and also for the electrolytic caps). I spent 3 hrs today looking at Capacitor specs only to come to the conclusion that they were all great. I suspect listening tests would not bare that out so I would be grateful of your experience, even if it's a starting point and some alternative suggestions. And if anyone knows of a supplier where i don't have to buy a bag of 100 ... Gggrrrreat... Question 3 - This may be a little contentious but if I don't ask then I'll remain ignorant and I don't like that idea. ? He suggested changing the simple xtal clock for a better cmos clock module. My understanding from the articles is that this clock is not being used to drive the data transfer to the DAC and is only used as a comparative signal against the spdif signal. So the question is ... should I upgrade this and why does it make a difference? (go easy on me guy's as I was shocked the first time someone told me to upgrade my cables, and now they cost as muck as my CD unit) Question 4 - I would like to have the power supplies and the DAC in two separate boxes... Are there any special considerations for this. I have mighty ambitions of adding a tube Analogue stage at some time (got to aim high) and it seems accepted practise to separate the supply circuits. Question 5 - I'd like to stack the input board and the DAC/Analogue board inside a half width case. Is there any further screening I should do? Also to make the casework easier and the connections to the interconnects better I was planning on fitting chassis based RCA sockets using silver plated units and silver wire connections (and later on, XLR's if they publish the circuit changes). Should I not fit the sockets to the board and solder straight into the holes(there's a picture somewhere where the board still has the sockets on it)? Also, should I twist the wires from the board to the sockets Question 6 - should I fit a filtered IEC socket to the PSU? Question 7 - is the resistor on pin 22 of the 9001 chip 980k? Question 8 - How much money is it worth spending on this design? I'm so sorry to be just taking from the forum (and asking all these questions) rather than being able to add to it.. but I have to start somewhere. Thanks Adrian (Hertford-UK) Hi Adrian, welcome to the grotto! lets see if we can give you some sort of answer 1) The ripple eater is the same as the JLH that Alex is partial too  If you look here and here you'll see how it has been passed on and developed, since Alex brought it here. Jon and I are finishing a new version of this board, which we hope to make available, but more on that. Either way, those who want one should be able to get one! Hopefully, Cricklewood Electronics have restocked on toshiba parts. 2) As far as I know, no one in the UK has built this DAC yet, so probably not looked into which parts to replace. Myself, I plan on building with the supplied parts first, and then going from there. However, other places apart from RS are Farnell, Rapid Electronics and CPC, but you probably already knew that! 3) Don't know, but don't discount it. 4)I built an amp and dac up recently, and have the transformers in a separate case to the PSU's and main bits, and no problem. I understand that having the traffo and PSU in a separate box can lead to an increase in PSU impedance, when you really want it to be low (This is one of the things that the JLH ripple eater does) But, we are talking specifics here, so in reality it should be fine. 5)There should be no problems with what you suggest. 6)Again, you can if you wish, although some find that a mains filter can flatten the sound. Myself, I'm happy with a X2 cap across the L/N. 7)I'll come back to you on that. 8)If you are going to drop £1k on it, I can recommend something that will blow your ears off  , If you are going to drop another £100 on it, probably. Another £500? Don't know but it really depends on the fun you'll get out of it, and also what DAC you have already. The previous Silcon Chip kit that Alex brought to us was a Headphone Amplifer (look in the SCHA section of the forum). The kit is from Jaycar, and costs £20-ish for the kit. After fettling, it beats some £500 headphone amps. |
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Will
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Post by Will on Jan 7, 2010 21:05:33 GMT
OK, question 7.
The circuit diagram shows 6k8 on pin22, but TI say:
DIR9001 data sheet Figure 8 / Table 5 and Figure17 indicate 680 ohms for the loop filter R value. The DIR9001 EVM user's guide schematic also shows a value of 680 ohms for the loop filter R in Figure 5. The 6.8K resistor may have been installed in error. Please replace it with 680 ohms. The R value impacts the clock recovery PLL loop filter response and stability. I would recommend the value shown in the data sheet and EVM users guide.
Which is nice, as the guy who designed this DAC kit has said that he made a typo, and we should use 680R on pin22.
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Post by Deleted on Jan 7, 2010 21:20:44 GMT
Thanks Will Now to confirm. Regards Alex Hi Guy's.... First off I'm a noob.. so I'm going to ask some stupid questions... I've built a few projects in the past (including a full CNC controller) but have never ventured into the world of Audio /HI Fi. I bumped into this kit while looking for a logic probe kit on the Jaycar site (please no laughs) and really fancied having a go, so it's on order!!! My plan is to use this DAC, driven by a Squeezebox 3 (classic!) then out into a Krell pre/ power amp and B&W Nautilus speakers. I'd love to get the best from the kit from the start so... After reading this thread and a similar thread on DIY Audio I have a few questions which must be only to obvious to everyone else. I'll ask them and if anyone can put me on the path I'd be grateful. On DIY Audio, alfredrofe suggested these parts as upgrades. Parts used Op Amp LM 49710 4.7 nf Polypropylene Capacitor RS 401-4766 68 nf Polypropylene Capacitor RS 401-4918 2.7nf Polypropylene Capacitor RS 401-4867 8.2nf Polypropylene Capacitor RS 401-4794 2.7nf Polypropylene Capacitor RS 401-4722 2.2nf Polypropylene Capacitor RS 401-4716 - later removed 100uf Oscon Farnell 121-7611 47uf Lo ESR Jaycar RE6332 Bead Ferrite WES FB12 Oscillator HyQ QXO8CBA 24m576 “Flea” Pink Fish Media “Ripple Eater” Rock Grotto Forum Question 1 - Where do I get the PCB for the "Ripple Eater" and is this the same as the JLH that Alex mentions in every post ( jokio). Everyone on the DIY forums seems to have them falling out of their pockets but after 4 hrs of searching I still don't know where to get a kit / pcb/schematics A. It is the same JLH , but with 4 x 4,700uF 10V Low ESR electrolytic capacitors instead of the original 2,200uF 10V Low ESR, although these would be O.K. The JLH is not available as a kit. There are currently no PCBs available, but I suggest you contact either Jon Clancy or Will Woodvine to express interest, as there may be a future new group buy if demand is sufficient.The schematic etc. is given in the "Tweaks" thread of the SC HA Zone . rockgrotto.proboards.com/index.cgi?board=chitchat&action=display&thread=3622&page=1Question 2 - It was great to get the RS item numbers however these are not available in the UK (they are AUS RS codes!). Can someone suggest alternatives which I can buy in the UK. (and also for the electrolytic caps). I spent 3 hrs today looking at Capacitor specs only to come to the conclusion that they were all great. I suspect listening tests would not bare that out so I would be grateful of your experience, even if it's a starting point and some alternative suggestions. And if anyone knows of a supplier where i don't have to buy a bag of 100 ... Gggrrrreat... A. Try searching the "film capacitor" area of RS for polypropylene capacitors of the values mentioned. MAKE SURE THEY HAVE 5mm LEAD SPACING! The same applies for the other major U.K. suppliers.Don't forget that you will need several of some types of polyprop capacitors. e.g. 2 x 68nF. One for the DIR9001, where the resistor value is actually 680 ohms, and 1 to replace the 100nF in the SPDIF INPUT circuit. Generic low ESR capacitors of the value and ratings specified should be satisfactory.n The blue and red capacitors in the photo of the DAC PCB that I posted, will give you the info about quantiities required. You will need to click on the photo a couple of times to get full size. Question 3 - This may be a little contentious but if I don't ask then I'll remain ignorant and I don't like that idea. ? He suggested changing the simple xtal clock for a better cmos clock module. My understanding from the articles is that this clock is not being used to drive the data transfer to the DAC and is only used as a comparative signal against the spdif signal. So the question is ... should I upgrade this and why does it make a difference? (go easy on me guy's as I was shocked the first time someone told me to upgrade my cables, and now they cost as muck as my CD unit) A. Yes, the Xtal/Clock does make a difference,as evidenced in the PFM Flea threads elsewhere. However, I am getting excellent results with the standard Xtal, although I will have a play with a Clock the same as Alfred's a little later on. Most people do not realise that a normal Xtal may vary by >1KHZ either way from it's nominal value, and this means added work for the PLL section of the I.C. Frequency Drift is also temperature related. An oscillator module has the potential to be less affected by temperature variations. Question 4 - I would like to have the power supplies and the DAC in two separate boxes... Are there any special considerations for this. I have mighty ambitions of adding a tube Analogue stage at some time (got to aim high) and it seems accepted practise to separate the supply circuits. I would try to keep the JLH near the DAC. A. For best results, solid state is best kept close together with good screening and short interconnect leads. Especially DACs! In ,this case, the INPUT PCB supplies 3.3V to the DAC PCB via a ribbon cable, as well as Data.Although, I do have my X-DAC V3 with it's separate Dual Regulated PSU. BUT, it was designed to work from an external AC supply transformer. Question 5 - I'd like to stack the input board and the DAC/Analogue board inside a half width case. Is there any further screening I should do? Also to make the casework easier and the connections to the interconnects better I was planning on fitting chassis based RCA sockets using silver plated units and silver wire connections (and later on, XLR's if they publish the circuit changes). Should I not fit the sockets to the board and solder straight into the holes(there's a picture somewhere where the board still has the sockets on it)? Also, should I twist the wires from the board to the sockets A. You should be able to do that. I elected to fit external RCA sockets of a better quality, as the mounting of the rear of the DAC PCB was a P.I.T.A. Besides I hated the idea of big holes with crappy RCA sockets poking through ! Twist the leads if they are more than a couple of CM long. Question 6 - should I fit a filtered IEC socket to the PSU? A. You could fit a 275VAC Varistor across the mains input, but the JLH and PSU PCB as modified in the Tweaks thread, is normally more than adequate. Question 7 - is the resistor on pin 22 of the 9001 chip 980k? A. No, it is 680 ohms Question 8 - How much money is it worth spending on this design? A. How long is a piece of string ? Start off with the basic kit and other parts, but fit the polyprops initially.Add the JLH as soon as you can get one. It WILL make a worthwhile improvement right across the board. Alfred has heard mine from my PC, and agrees that it already is not disgraced in comparison to my highly modified X-DAC V3.It is not quite as good yet, but is capable of considerably more tweaking. I'm so sorry to be just taking from the forum (and asking all these questions) rather than being able to add to it.. but I have to start somewhere. Thanks Adrian (Hertford-UK) |
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Post by Deleted on Jan 8, 2010 8:11:19 GMT
Jeff, Does the Jaycar kits' switching board come complete with the switches that petrude through the front panel as in Alexs build? PS did you get your switch board to behave? Chris I'm reckoning on buying the Jaycar kit, their PSU board, transformer (which one?), other panel hardware and make my own case. Apart from mods would that be the whole shooting match? Chris I will have to speak for Jeff, as as he was due to be at the airport at 5AM. Yes, the pushbutton switches with integral blue LEDs come with the kit. No, Jeff has not had time to find the fault in the switching PCB. There is very little to go wrong there, other than dry joints on the THIN Blue LED leads, and IDP cable problems which can be verified using a DMM. The problem with the whole 3 blue LEDs, was in my case due to solder not flowing properly around the thin blue LEDs leads at the same location each time, due to those thin leads being much smaller than the diameter of the drilled holes. I doubt that there would have been a problem if the leads of the LEDs had been the usual thickness. A reluctance to burn the shit out of the plastic switches with the small soldering iron used, was the cause in my case. Perhaps the LED leads' PCB holes could be tinned beforehand to help with the solder flow later ? The other parts also needed are an IEC socket and panel mounting fuse holder with M205 500mA fuse.Due to weight,the transformer would be best obtained locally ,or from the U.K. It is a 230V Primary 15-0-15VAC 20 OR 30VA Toroidal transformer. Alex Cheers Alex, EDIT Just noticed this is my 1066th post. My surname is of direct Norman origin, so to quote... You don't frighten us, English pig-dogs! Go and boil your bottoms, son of a
silly person! Ah blow my nose at you, so-called "Arthur Keeeng"! You and
all your silly English Knnnnnnnn-ighuts!!!
Ah don' wanna talk to you no more, you empty-headed animal food-trough
wiper! Ah fart in your general direction! Your mother was a hamster, and
your father smelt of elderberries! ;D |
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Post by bpgoa on Jan 8, 2010 15:06:26 GMT
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Will
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Post by Will on Jan 8, 2010 19:22:32 GMT
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Will
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Post by Will on Jan 8, 2010 19:43:48 GMT
It's also worth ordering up some BC550C transistors, as well, for the JLH BC550CCricklewood seem to be the only place in the UK that have them in stock. That seems a really bizarre situation. |
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Post by Deleted on Jan 8, 2010 20:02:11 GMT
Re the 2n2 output capacitors: I fitted 100pf polyprop there to give a small degree of cable choice . With 2.2pf there is likely to be quite a bit of audible difference between output cable types.IMO, 2n2 is overkill at that location, and audibly degrades soundstage depth.
The 22pf capacitors on the DAC PCB are redundant ,unless NE5534 is used. Leave them out.
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Post by bpgoa on Jan 9, 2010 23:36:34 GMT
is there anyone out there that can confirm (or otherwise)that the capacitors i have suggested in my previous post are of the correct type.
thanks
Adrian
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Post by Deleted on Jan 10, 2010 0:21:55 GMT
Adrian
The 100nF SPDIF Input capacitor is best replaced by a 68nF polypropylene cap, like the 68nF on pin22 of DIR9001. The type you have specified is not polypropylene. Typical generic 100nF as specified for the SPDIF Input are not really suited for high speed data due to dielectric absorption issues.(16/44.1 = 2.8MHZ) The actual capacitance value is not critical, and 100nF polypropylene is hard to come by, and most likely a litle too bulky.
Why the fixation with big brand name capacitors in other locations ? They often add their own colouration to a circuit. Why not try the supplied Suntan caps initially ? There are far better areas for tweaking than bypass caps at this early stage.Oscons may be O.K. in a couple of locations, but I have never found the need for expensive brand name capacitors.
I am not across U.K. suppliers, but will see if I can locate suitable polyprops for the DAC PCB.
Alex.
P.S.
Not having much success with U.K. suppliers. Perhaps another U.K. member knows of other sources locally ?
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Post by bpgoa on Jan 10, 2010 9:15:52 GMT
Hi Alex, At this point in my audio building career (not built anything yet  -) )I don't really have an opinion. so... I'm doing the next best thing and trying to follow other peoples. from what I've read, most people seem to be fixated with capacitor brand choice. The whole point of the above post was to try and canvas other peoples views on those capacitors suitability. I think what you are saying is stop and listen to it as it is THEN change and play. Is that correct? Thanks Adrian P.S. What about putting this on it's head in there?
www.cricklewoodelectronics.com/Cricklewood/product.php?productid=2042&cat=155&page=1 |
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Post by Deleted on Jan 10, 2010 9:25:58 GMT
Hi Alex, At this point in my audio building career (not built anything yet :-) )I don't really have an opinion. so... i'm doing the next best thing and trying to follow other peoples. from what i've read, most people seem to be fixated with capacitor brand choice. The whole point of the above post was to try and canvas other peoples views on those capacitors suitability. I think what you are saying is stop and listen to it as it is THEN change and play. Is That correct? thanks Adrian Adrian That is exactly what I am saying. Surprisingly, the lowly Suntan low ESR 2,200 uF 10V caps have been found by the majority of JLH constructors to be the best choice. If you don't try the original caps as supplied in the Jaycar kit first, then you will never know if the others are really an improvement. With the polyprops though, that is an entirely different story. Not only are they a superior type of capacitor, but they are also likely to be of a closer tolerance, (2% or 5%) Alex |
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Post by Deleted on Jan 10, 2010 9:34:55 GMT
adrian
Re the link, There will be no advantage with using that in the SPDIF input, as any value polyprop from 33nF is O.K. in that part of the circuit, I am currently using 33nf while I wait delivery of the 68nf from RS.
Alex
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Post by bpgoa on Jan 10, 2010 9:48:54 GMT
Adrian That is exactly what I am saying. Surprisingly, the lowly Suntan low ESR 2,200 uF 10V caps have been found by the majority of JLH constructors to be the best choice. If you don't try the original caps as supplied in the Jaycar kit first, then you will never know if the others are really an improvement. With the polyprops though, that is an entirely different story. Not only are they a superior type of capacitor, but they are also likely to be of a closer tolerance, (2% or 5%) Alex I think the easiest thing for me to do is to order the polypropylene caps from RS in Australia... (as alfredo so kindly provided the part numbers). I should have just done that in the first place... it looks like i spent 10hrs finding the wrong components. Adrian p.s. post a link to the cap you ordered so as i get an idea of what your looking at. |
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Post by Deleted on Jan 10, 2010 9:56:03 GMT
Adrian That is exactly what I am saying. Surprisingly, the lowly Suntan low ESR 2,200 uF 10V caps have been found by the majority of JLH constructors to be the best choice. If you don't try the original caps as supplied in the Jaycar kit first, then you will never know if the others are really an improvement. With the polyprops though, that is an entirely different story. Not only are they a superior type of capacitor, but they are also likely to be of a closer tolerance, (2% or 5%) Alex I think the easiest thing for me to do is to order the polypropylene caps from RS in Australia... (as alfredo so kindly provided the part numbers). I should have just done that in the first place... it looks like i spent 10hrs finding the wrong components. Adrian Adrian Have you thought about seeing if Will and Chris are interested in a joint order of these hard to find parts ? Alex |
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Post by bpgoa on Jan 10, 2010 10:14:43 GMT
Adrian Have you thought about seeing if Will and Chris are interested in a joint order of these hard to find parts ? Alex Good plan.... Will ? Chris? PM Me if you want to share the order... |
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Will
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Post by Will on Jan 10, 2010 10:36:42 GMT
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Post by Deleted on Jan 10, 2010 10:58:51 GMT
Will No advantage to 100nF polyprop and likely to be bulkier. Get 2 x 68nF polyprop, one for pin 22 of the DIR9001 and the other for the SPDIF Input. Many SPDIF inputs use values as low as 10NF. Mine is fine with 33nF, but will be fitted with 68nF, and Alfred is using 2 x 68nF as mentioned. Did you mean 68nf instead of 68pf ? Alex |
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Post by Will on Jan 10, 2010 12:06:45 GMT
Thanks Alex, yes I did.
Have changed the link, accidents happen when you are getting ready for a snowball fight (I lost!)
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Post by Deleted on Jan 10, 2010 13:00:39 GMT
Adrian Have you thought about seeing if Will and Chris are interested in a joint order of these hard to find parts ? Alex .. I'm only a follower on these things and have not had the time to get into it yet. (read as, have not even ordered the kit). I hope to do so at the end of this month/beginning of next, I should have caught up with the house/business list by then  (delayed by weather) I also plan to be more methodical this time, I got in a right mess on the SCHA! So basically, yes, good plan, but no idea on timing. Chris |
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Post by bpgoa on Jan 10, 2010 19:04:04 GMT
Those are the caps I've been looking for... The Vishay's
Here is a list of all the caps, modified to take in Alex's suggestions and the corrections in the articles... but please check
Capacitor list
Input board
1 x 470uf 6.3v Electrolytic
2 x 22uf 6.3v Electrolytic
3 x 1uf 6.3v Electrolytic used in the IRDA circuit leave as they are
1 x 470nf MKT Metalized Polyester
10 x 100nf MKT Metalized Polyester – 9 used for decoupling ok - Replace 1 in the spdif input with a 68nf
1 x 68nf MKT Metalized Polyester
1 x 4.7nf MKT Metalized Polyester
1 x 1nf MKT Metalized Polyester
4 x 33pf Ceramic
DAC Board
2 x 47uf 16v Electrolytic (in PSU section) upgraded in the kit to 100uf 25v
1 x 47uf 6.3v Electrolytic replace with a low ESR Suntan 47uf cap
4 x 10uf 6.3v Electrolytic upgraded in the kit to 47uf 6.3v
9 x 100nf MKT Metalized Polyester – used for decoupling ok as they are
2 x 27nf MKT Metalized Polyester
4 x 8.2nf MKT Metalized Polyester
4 x 2.7nf MKT Metalized Polyester
2 x 2.2nf MKT Metalized Polyester (Audio out) - replace with 2.2pf caps
6 x 22pf Ceramic
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Post by bpgoa on Jan 10, 2010 19:10:01 GMT
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Post by Deleted on Jan 10, 2010 20:53:00 GMT
Adrian
Replacing the 2n2 caps with 2.2pf caps will do almost nothing.You can get that much capacitance from stray capacitance, or the internal capacitance of the actual RCA output socket !
You can try leaving them out, which may make the unit quite sensitive to the type and length of output lead, or you could try fitting 47pf or preferably 100 pf at that location.
Alex
P.S.
I took the liberty of editing your previous post for clarity reasons.
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Will
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Post by Will on Jan 10, 2010 22:01:18 GMT
Are we suggesting it is changed to 68nf a post above #67?
Also
Are these the filter caps, that are suitable to change to pp?
Plus a question. If you wanted a balanced output from this dac, would you tap into the outputs of IC's 7,8,10 and 11? ;D
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Post by Deleted on Jan 10, 2010 22:26:02 GMT
Are we suggesting it is changed to 68nf a post above #67? Also Are these the filter caps, that are suitable to change to pp? Plus a question. If you wanted a balanced output from this dac, would you tap into the outputs of IC's 7,8,10 and 11? ;D Will I wouldn't recommend the 100nF polyprop for bypass use. It will be fine for SPDIF input, but take into account the price  , and minimum rquirements of 5. 68nF polyprop will work just as well there. Re other capacitors, please check your email. Due to requests,SC will publish an add on balanced output stage for this DAC. It will not be a redesign of the original DAC PCB. Alex |
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, If you are going to drop another £100 on it, probably. Another £500? Don't know but it really depends on the fun you'll get out of it, and also what DAC you have already.
-) )I don't really have an opinion. so... I'm doing the next best thing and trying to follow other peoples. from what I've read, most people seem to be fixated with capacitor brand choice. The whole point of the above post was to try and canvas other peoples views on those capacitors suitability. 
(delayed by weather)
, and minimum rquirements of 5. 68nF polyprop will work just as well there.